Collections of photosynq measurements (Ternopil)

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A. I. Herts, O. B. Kononchuk

Ternopil Volodymyr Hnatiuk National Pedagogical University 2 Kryvonosa st., Ternopil, 46027

CHANGE OF PARTICULAR PHYSIOLOGICAL PARAMETERS OF PHASEOLUS VULGARIS L. PLANTS BY DIFFERENT CONCENTRATION OF NANOMOLYBDENUM

Molybdenum plays an important role in many physiological processes of plants as a part of more than twenty enzymes. First of all, this trace element influences the nitrogen metabolism of plants as a component of nitrate reductase, nitrogenase, activates the amination and transamination reaction required for the synthesis of leghemoglobin etc., which is especially important for legumes. To increase its effectiveness molybdenum can be used in the form of nanopreparations, which have significantly higher biological reactivity compared to conventional micro fertilisers due to the longer and more active penetration of the active ingredient from nanoparticles into plants and its less phytotoxic influence.

The purpose of our study was to find out the most effective concentration of nanomolybdenum preparation by F. D. Ovcharenko Institute of Biocolloidal Chemistry) for foliar feeding of a plant. Bukovynka cultivar of beans (Phaseolus vulgaris L.) growing in the greenhouse (in the stage of the first true leaves) has been used in the experiments. Plants were sprayed with aqueous solutions of molybdenum in concentrations of 120, 240 and 360 mg/l (respectively Mo120, Mo240, Mo360) or with the distilled water (control).

After treatment of the plant with molybdenum concentration of 240 mg/l the mass of above-ground parts of plants significantly increased by 128.4% and by 46.3% and 39.7% for the concentration of 120 and 360 mg/l respectively. A similar trend was found with the increased weight of fresh leaves, by 172.4%, 48.3% and 42.4% (control – 2.03 ± 0.19) and their total area - by 64.0%, 29.6% and 22.8% compared to the control (176.7 ± 16.,8 cm2).

Spectrophotometric determination of chlorophyll a amount in leaves showed its highest increase in the alteration Mo240 – by 18.4% compared to controls (70.0 ± 1.5 mg / 100 g of fresh weight); after treatment of plants by concentrations of 120 and 360 mg/l the amount of chlorophyll a increased by 6.3% and 10.0% respectively. Increased chlorophyll b and basic kinds of carotenoids were significant after applying the maximum concentration of molybdenum (360 mg/l) - by 36.2% and 39.3% compared to the control (155.4 ± 2.7 mg/100 g of fresh weight). Molybdenum concentration of 240 mg/l induced the increase of the amount of these pigments by 18.5% and 5.3%, and the concentration of 120 mg/l - by 4.2% and 7.0% before control, respectively.

All these changes can indicate certain peculiarity of plant metabolism reaction to molybdenum and the possible negative effect of high concentration of the microelement in 360 mg/l. Since it is known that the increase of plant carotenoids plays an important role in the formation of the protective mechanisms of photosynthetic apparatus against adverse factors.

In order to justify the above mentioned morphological and physiological differences, the condition of PS II of beans was estimated by a method of induced fluorescence of chlorophyll a. Correlation matrix of fresh weight of above-ground parts of plant, areas of leaf plates and fluorescence parameters of chlorophyll a allow to distinguish a few parameters as follows: relative chlorophyll content (SPAD), ФPS II, the vitality index (Rfd), as the parameters that positively correlate with the increase of the vegetative weight of plants - the correlation coefficient is 0.51-0.53.

It has been found out that the increase in weight of above-ground parts of plants, the weight and area of leaf surface is caused by chlorophyll amount and the level of quantum yield of electron transport in photosystem II. The increase of nonphotochemical quenching (φNPQ) (r = -0.50) in PS II reduces the photosynthetic productivity of plants.

To estimate the impact of different concentrations of molybdenum ions on parameters characterizing the state of PS II the one-way ANOVA test was conducted along with application of Tukey's test. It was found that ФPS II, φNPQ, the fraction of PSII centres that are open (qL), the relative chlorophyll content (SPAD) and the vitality index (Rfd) are sensitive (P <0.05) to changes in the nanomolibdenum concentration in the solution for foliar feeding of plants.

It is worth mentioning that nanomolibdenum concentration of 240 mg / l has a positive effect on the primary processes of photosynthesis. Under such condition, the portion of light for Phaseolus vulgaris, which is realised through photochemical processes, has increased as evidenced by the parameter of PSII, and the level of the quantum yield of nonphotochemical quenching (φNPQ) has significantly reduced.

Nanomolibdenum concentration of 360 mg/l in the solution for foliar feeding of plants, reduces the Fm'-level of fluorescence. As a result, the role of nonphotochemical way of quenching the light energy increases. Thus, through inhibition of photosynthetic efficiency of photosystem II and the increasing role of nonphotochemical way of light energy transformation by the plant it is not appropriate to raise the concentration of nanomolibdenum from 240 mg/l to 360 mg/l. Thus, nanomolibdenum with the concentration of 240 mg/l has the maximum stimulating effect in terms of accumulation of fresh weight of the above-ground parts of plants, area of leaf surface and the content of chlorophyll a and b for Bukovynka cultivar of beans.

We received a number of chlorophyll a fluorescence parameters, which show not only short-term but also long-term after-effect of molybdenum on photosynthetic activity of the beans. A group of parameters of chlorophyll a fluorescence that can be used for the rapid estimation of long-term effect of microelements has been singled out.TukeySPAD.jpg TukeyPhiNPQ.jpg TukeyPhiNO.jpg Tukey-Phi2.jpg

http://journal.chem-bio.com.ua/nomery-zhurnalu-2017-r/statti-nomera-1-68-2017/item/529-zmina-deyakykh-fiziolohichnykh-pokaznykiv-roslyn-phaseolus-vulgaris-l-za-riznoyi-kontsentratsiyi-nanomolibdenu

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